Water reactive hydrogen fuel cell power system

ABSTRACT

A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of priority of U.S. Provisional PatentApplication Ser. No. 61/411,244 filed on Nov. 8, 2010, and to U.S.patent application Ser. No. 13/291,815 filed on Nov. 8, 2011, and toU.S. Provisional Patent Application Ser. No. 61/595,972 filed Feb. 7,2012, and is related to U.S. patent application Ser. No. 12/750,527filed on Mar. 30, 2010, the entire disclosures of which are incorporatedherein by reference. This application is a continuation-in-part of U.S.patent application Ser. No. 13/291,815 filed on Nov. 8, 2011 whichclaims benefit of priority of U.S. Provisional Patent Application61/411,244 filed Nov. 8, 2011.

FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with government support under contract numberDE-FG36-08GO88108 awarded by the U.S. Department of Energy. The U.S.Government has certain rights in this invention.

TECHNOLOGICAL FIELD

This technology generally relates to of hydrogen-generating fuel cellsystems and methods, and more particularly, to systems and methods forgenerating hydrogen using sodium silicide, sodium silica gel, ormulti-component mixtures that are reacted with water or water solutions.

BACKGROUND

Fuel cells are electrochemical energy conversion devices that convert anexternal source fuel into electrical current. Many fuel cells usehydrogen as the fuel and oxygen (typically from air) as an oxidant. Theby-product for such a fuel cell is water, making the fuel cell a verylow environmental impact device for generating power.

Fuel cells compete with numerous other technologies for producing power,such as the gasoline turbine, the internal combustion engine, and thebattery. A fuel cell provides a direct current (DC) voltage that can beused for numerous applications including stationary power generation,lighting, back-up power, consumer electronics, personal mobilitydevices, such as electric bicycles, as well as landscaping equipment,and other applications. There are a wide variety of fuel cellsavailable, each using a different chemistry to generate power. Fuelcells are usually classified according to their operating temperatureand the type of electrolyte system that they utilize. One common fuelcell is the polymer exchange membrane fuel cell (PEMFC), which useshydrogen as the fuel with oxygen (usually air) as its oxidant. It has ahigh power density and a low operating temperature of usually below 80°C. These fuel cells are reliable with modest packaging and systemimplementation requirements.

The challenge of hydrogen storage and generation has limited thewide-scale adoption of PEM fuel cells. Although molecular hydrogen has avery high energy density on a mass basis, as a gas at ambient conditionsit has very low energy density by volume. The techniques employed toprovide hydrogen to portable applications are widespread, including highpressure and cryogenics, but they have most often focused on chemicalcompounds that reliably release hydrogen gas on-demand. Three broadlyaccepted mechanisms used to store hydrogen in materials are absorption,adsorption, and chemical reaction.

In absorptive hydrogen storage for fueling a fuel cell, hydrogen gas isabsorbed directly at high pressure into the bulk of a specificcrystalline material, such as a metal hydride. Metal hydrides such asMgH₂, NaAlH₄, and LaNi₅H₆, can be used to store the hydrogen gasreversibly. However, metal hydride systems often suffer from poorspecific energy (i.e., a low hydrogen storage to metal hydride massratio) and poor input/output flow characteristics. The hydrogen flowcharacteristics are driven by the endothermic properties of metalhydrides (the internal temperature drops when removing hydrogen andrises when recharging with hydrogen). Because of these properties, metalhydrides tend to be heavy and require complicated systems to rapidlycharge and/or discharge them. For example, see U.S. Pat. No. 7,271,567for a system designed to store and then controllably release pressurizedhydrogen gas from a cartridge containing a metal hydride or some otherhydrogen-based chemical fuel. This system also monitors the level ofremaining hydrogen capable of being delivered to the fuel cell bymeasuring the temperature and/or the pressure of the metal hydride fuelitself and/or by measuring the current output of the fuel cell toestimate the amount of hydrogen consumed.

In adsorption hydrogen storage for fueling a fuel cell, molecularhydrogen is associated with the chemical fuel by either physisorption orchemisorption. Chemical hydrides, such as lithium hydride (LiH), lithiumaluminum hydride (LiAlH4), lithium borohydride (LiBH4), sodium hydride(NaH), sodium borohydride (NaBH4), and the like, are used to storehydrogen gas non-reversibly. Chemical hydrides produce large amounts ofhydrogen gas upon reaction with water as shown below:

NaBH₄+2H₂O→NaBO₂+4H₂

To reliably control the reaction of chemical hydrides with water torelease hydrogen gas from a fuel storage device, a catalyst must beemployed along with control of the water's pH. Additionally, thechemical hydride is often embodied in a slurry of inert stabilizingliquid to protect the hydride from early release of its hydrogen gas.

In chemical reaction methods for producing hydrogen for a fuel cell,often hydrogen storage and hydrogen release are catalyzed by a modestchange in temperature or pressure of the chemical fuel. One example ofthis chemical system, which is catalyzed by temperature, is hydrogengeneration from ammonia-borane by the following reaction:

NH₃BH₃→NH₂BH₂+H₂→NHBH+H₂

The first reaction releases 6.1 wt. % hydrogen and occurs atapproximately 120° C., while the second reaction releases another 6.5wt. % hydrogen and occurs at approximately 160° C. These chemicalreaction methods do not use water as an initiator to produce hydrogengas, do not require a tight control of the system pH, and often do notrequire a separate catalyst material. However, these chemical reactionmethods are plagued with system control issues often due to the commonoccurrence of thermal runaway. See, for example, U.S. Pat. No.7,682,411, for a system designed to thermally initialize hydrogengeneration from ammonia-borane and to protect from thermal runaway. See,for example, U.S. Pat. Nos. 7,316,788 and 7,578,992, for chemicalreaction methods that employ a catalyst and a solvent to change thethermal hydrogen release conditions.

In view of the above, there is a need for an improved hydrogengeneration system and method that overcomes problems or disadvantages inthe prior art.

SUMMARY

The hydrogen fuel cell power system described below includes threeprimary subsystems, including a fuel cell, a water feed tray system, anda fuel cartridge. This system is designed for the class of fuel cellsystems called “water-reactive.” In a water-reactive system, water (or aliquid solution) is combined with a powder to generate hydrogen for afuel cell system. These reaction types can use a range of powders suchas sodium silicide, sodium silica gel, sodium borohydride, sodiumsilicide/sodium borohydride mixtures, aluminum, and others. Activators,catalysts, or additives can be added to the powder to control waterdispersion through the powder or water absorption of the reactionby-products. Additives to the powder can also include defoamers, such asoils, as well as similar materials to distribute local reaction sitesand/or temperatures to result in a more uniform reactivity and heatdistribution in the fuel cartridge and to control reaction conditions,including, for example, the chemical and physical nature of the reactionproducts and by-products. Powder size can be controlled to facilitatewater transport, reaction rate, and byproduct water absorption.Activators, catalysts, or other additives can also be added to the waterin order to form a liquid solution at varying conditions.

The reactant fuel material can include stabilized alkali metal materialssuch as silicides, including sodium silicide powder (NaSi), andsodium-silica gel (Na—SG). The stabilized alkali metal materials canalso be combined with other reactive materials, including, but notlimited to, ammonia-borane (with or without catalysts), sodiumborohydride (mixed with or without catalysts), and an array of materialsand material mixtures that produce hydrogen when exposed to heat oraqueous solutions. The mixture of materials and the aqueous solutionscan also include additives to control the pH of the waste products, tochange the solubility of the waste products, to increase the amount ofhydrogen production, to increase the rate of hydrogen production, and tocontrol the temperature of the reaction. The aqueous solution caninclude water, acids, bases, alcohols, and mixtures of these solutions.Other examples of the aqueous solutions can include methanol, ethanol,hydrochloric acid, acetic acid, sodium hydroxide, and the like. Theaqueous solutions can also include additives, such as a coreactant thatincreases the amount of H₂ produced, a flocculant, a corrosioninhibitor, or a thermophysical additive that changes thermophysicalproperties of the aqueous solution. Example flocculants include calciumhydroxide, sodium silicate, and others, while corrosion inhibitors caninclude phosphates, borates, and others. Further, the thermophysicaladditive can change the temperature range of reaction, the pressurerange of the reaction, and the like. Further, the additive to theaqueous solution can include mixtures of a variety of differentadditives.

The claimed invention can include a removable/replaceable fuel cartridgethat is inserted into a water feed tray system. A fuel cell can beconnected to the water feed tray system encompassing the fuel cartridge.In the process of this connection, the fuel cartridge forms a waterconnection with the water feed tray and a hydrogen gas connection withthe fuel cell. The water feed tray can be designed to store and bere-filled with water. The water feed tray system can be designed not tooutput water until the water feed tray is connected to a fuel cartridge.As water enters the fuel cartridge from the water feed tray, hydrogen isgenerated and delivered to the fuel cell. Upon disconnection of thewater feed tray and fuel cell, a valve in the water tray closes, whichin turn stops water flow in the water tray. In addition, a springmechanism in the water feed tray ejects the fuel cartridge from thewater feed tray which disconnects the water flow path to the fuelcartridge. Either or both of these configurations and techniques stopwater flow and ceases production of hydrogen. In another exampleimplementation, a mechanical flow valve or similar mechanism can beemployed to stop water flow into the fuel cartridge while the fuelcartridge remains connected. This in turn, stops hydrogen from beinggenerated. The flow valve can be a physical switch controlled by a useror an electronically controlled switch. Likewise, in another exampleimplementation, the flow can be controlled by a pump to turn off waterflow while the fuel cartridge is still engaged or to pump water if flowis desired.

In one example implementation, the water feed tray and fuel cell can beconstructed to effectively function as a single sub-system with areplaceable fuel cartridge being a removable/replaceable component. Inanother implementation, the water feed tray and fuel cartridge can beconstructed to effectively function as a single sub-system with theentire sub-system being removable/replaceable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a hydrogen fuel cell power system, including afuel cell, water feed tray, and a fuel cartridge in accordance with theclaimed invention.

FIG. 2 illustrates a water feed fuel cell system and fuel cartridge andits related inputs and outputs.

FIG. 3 shows an example of a water feed fuel cell system with arefillable water door and a fuel cartridge in accordance with theclaimed invention.

FIGS. 4A-4B illustrates structural characteristics of a water feed trayshown with a fuel cartridge inserted in the water feed tray.

FIG. 5A shows an exploded view of a water feed fuel cell system shownwith a fuel cartridge. FIG. 5B shows a side view of the water trayinsert. FIG. 5C shows the bottom of the water tray insert.

FIGS. 6A and 6B illustrate a sliding lock mechanism used in a hydrogenfuel cell power system in an open view and in a closed view inaccordance with the claimed invention.

FIG. 6C illustrates water feed tray, fuel cartridge, and fuel cellsub-systems with a latch connection mechanism.

FIG. 6D is a cross-sectional view of a water feed tray and fuelcartridge in accordance with the claimed invention.

FIG. 7A is a perspective view of a water feed tray with a fuel cartridgeinserted. FIG. 7B is a side view of a water feed tray with a fuelcartridge inserted. FIG. 7 C is a top view of a water feed tray with afuel cartridge inserted.

FIG. 8A illustrates a bellows spring assembly configured to store,pressurize, and output water in a water feed tray in accordance with theclaimed invention.

FIGS. 8B and 8C illustrate a bellows spring assembly in accordance withthe claimed invention in a nominal compressed state and in a loadedstate, respectively.

FIGS. 8D and 8E illustrate a bellows spring assembly and locking shelfin accordance with the claimed invention in a disengaged position and inan engaged position, respectively.

FIG. 8F illustrates a bellows access door in accordance with the claimedinvention in an engaged position.

FIG. 9A is a side view of a tube-connection water limiting orifice inaccordance with the claimed invention. FIG. 9B is a cross-sectional viewof the section A-A as indicated in FIG. 9A. FIG. 9C is a perspectiveview a tube-connection water limiting orifice in accordance with theclaimed invention.

FIG. 10A shows a top view of a disk-type water flow limiting orifice inaccordance with the claimed invention. FIG. 10B shows a side view of adisk-type water flow limiting orifice in accordance with the claimedinvention. FIG. 10C shows a perspective view of a disk-type water flowlimiting orifice in accordance with the claimed invention.

FIG. 11 illustrates structural components for the top of a bellowsassembly to lock the tray door open when refilling water in a fuel cellsystem in accordance with the claimed invention.

FIGS. 12A and 12B are top and perspective views, respectively, thatillustrate a locking mechanism to lock the fill door open when refillingwater in a fuel cell system in accordance with the claimed invention.

FIGS. 13A and 13B are cross sectional views illustrating structuraldetails of a fuel cartridge for use in a hydrogen fuel cell power systemin accordance with the claimed invention.

FIG. 13C is front view of an angled needle value in accordance with theclaimed invention. FIG. 13D is a perspective view of an angled needlevalve in accordance with the claimed invention.

FIG. 14A is a side view which illustrates further structural details ofa fuel cartridge canister for use in a hydrogen fuel cell power systemin accordance with the claimed invention. FIG. 14B is another side viewwhich illustrates further structural details of a fuel cartridgecanister for use in a hydrogen fuel cell power system in accordance withthe claimed invention. FIG. 14C is top view which illustrates furtherstructural details of a fuel cartridge canister for use in a hydrogenfuel cell power system in accordance with the claimed invention. FIG.14D is yet another side view which illustrates further structuraldetails of a fuel cartridge canister for use in a hydrogen fuel cellpower system in accordance with the claimed invention. FIG. 14E is aperspective view which illustrates further structural details of a fuelcartridge canister for use in a hydrogen fuel cell power system inaccordance with the claimed invention. FIG. 14F is another perspectiveview which illustrates further structural details of a fuel cartridgecanister for use in a hydrogen fuel cell power system in accordance withthe claimed invention.

FIG. 14G is a perspective view which illustrates a reactant retentionscreen for a fuel cartridge in accordance with the claimed invention.FIG. 14H is a top view which illustrates a reactant retention screen fora fuel cartridge in accordance with the claimed invention.

FIG. 15A shows a chemical scrubbing pathway for acquiring high purityhydrogen by controlling the exit flow over a filter bed integrallyformed in a cap of a fuel cartridge in accordance with the claimedinvention.

FIG. 15B shows a chemical scrubbing maze for acquiring high purityhydrogen by controlling the exit flow over a filter bed integrallyformed in a cap of a fuel cartridge in accordance with the claimedinvention.

FIG. 15C shows a perspective view of an overmolded face seal gasketincorporated into a cap of a fuel cartridge in accordance with theclaimed invention.

FIG. 15D shows a side view of an overmolded face seal gasketincorporated into a cap of a fuel cartridge in accordance with theclaimed invention.

FIG. 16A shows a tool to crimp a metallic fuel cartridge body to aplastic fuel cartridge cap for use in a hydrogen fuel cell power systemin accordance with the claimed invention.

FIG. 16B is a cross-sectional view of a fuel cartridge that has beenassembled using a roll-over crimp and the crimping tool of FIG. 16A.

FIG. 17A shows an example of a perspective view of a cartridge valveintegrally mounted to a fuel cartridge cap in accordance with theclaimed invention. FIG. 17B shows an example of a top view of acartridge valve integrally mounted to a fuel cartridge cap in accordancewith the claimed invention. FIG. 17C shows an example of a closeup viewof area C in FIG. 17D. FIG. 17D shows an example of a cross sectionalview of the section A-A as indicated in FIG. 17B.

FIG. 18A shows a canister with a coiled reaction feed tube for use in ahydrogen fuel cell power system in accordance with the claimedinvention.

FIG. 18B shows a canister with a T-fitting and coiled reaction feed tubefor use in a hydrogen fuel cell power system in accordance with theclaimed invention.

FIGS. 19A and 19B show an automatic mechanical water control valve andplunger for use in a hydrogen fuel cell power system in accordance withthe claimed invention in an open position and a closed position,respectively.

FIG. 20 shows springs to “eject” cartridges from the tray of a hydrogenfuel cell power system in accordance with the claimed invention.

FIGS. 21A and 21B show a normally closed needle valve for use in ahydrogen fuel cell power system in accordance with the claimed inventionin a perspective view and a cross sectional view, respectively.

FIG. 22 shows a system in accordance with the claimed invention charginga cellular telephone.

FIG. 23A shows a silicone sheet for fluid isolation in a fuel cellsystem in accordance with the claimed invention.

FIG. 23B shows a water feed tray needle and a silicone sheet providingfluid isolation in a fuel cell system in accordance with the claimedinvention.

FIG. 23C shows a bottom view of a silicone sheet for fluid isolation ina fuel cell system in accordance with the claimed invention.

FIGS. 24A and 24B illustrates a segmented fuel cartridge and a rotatableactuator manifold in accordance with the claimed invention as therotatable actuator manifold moves from a first position to a secondposition, respectively.

FIGS. 25A and 25B schematically illustrate a rotatable actuator manifoldin accordance with the claimed invention in side and top views,respectively.

FIGS. 26A and 26B schematically illustrate a magnetic poppet safety stopvalve in accordance with the claimed invention in open and closed views,respectively.

DETAILED DESCRIPTION

FIG. 1 shows one example of a water-reactive, hydrogen-fueled powersystem 100 in accordance with the claimed invention. The system 100includes a fuel cartridge 120, a water feed tray 130, and a fuel cell110. Fuel cartridge 120 includes a reactant fuel material 177. Fuelcartridge 120 can be a physical device separate from water feed tray 130or can be integral to water feed tray 130.

The reactant fuel material 177 can include stabilized alkali metalmaterials, including powders such as sodium silicide, sodium silica gel,sodium borohydride, sodium silicide/sodium borohydride mixtures,aluminum, and others. Activators, catalysts, and/or additives can beadded to the reactant fuel material 177 to control water dispersionthrough the reactant fuel material 177 or water absorption of thereaction by-products. Additives to the reactant fuel material 177 canalso include defoamers, such as oils, such as mineral oils, as well asother materials to distribute local reaction temperatures to result in amore uniform heat distribution in the fuel cartridge 120. The reactantfuel material 177 powder size can be controlled to facilitate watertransport, reaction rate, and byproduct water absorption. For example,the powder size of the reactant fuel material 177 can be varied fromless than 1 mm to 9 mm. In one example implementation, the powder sizeof the sodium silicide was from approximately 4 mm to 6 mm. This powdersize is made large enough to eliminate problematic binding when water oranother aqueous solution is added to the fuel cartridge. Instead ofadding water to a too-fine powder that is susceptible to binding whenwet, this reactant fuel configuration allows for the added water 199 toeffectively reach fresh powder as the water 199 is added to the fuelcartridge 120.

The reactant fuel material 177 can also include stabilized alkali metalmaterials such as silicides, including sodium silicide powder (NaSi),and sodium-silica gel (Na—SG). The stabilized alkali metal materials canalso be combined with other reactive materials, including, for example,ammonia-borane (with or without catalysts), sodium borohydride (mixedwith or without catalysts), and an array of materials and materialmixtures that produce hydrogen when exposed to heat or aqueoussolutions. In one example implementation, the reactant fuel material 177includes stabilized alkali metal materials and such optionalcoreactants.

The water feed tray 130 can be filled with water 199 by a user.Activators, catalysts, or other additives can also be added to the water199 in order to form a liquid solution. The water feed tray 130 includesa mechanism to pressurize the water 199. One example pressurizationmechanism shown in FIG. 1 can include a spring assembly 231 in bellows160 that pressurizes water 199 to flow through check valve 140 andpoppet 150 and into fuel cartridge 120. The spring assembly 231 can bemounted in the bellows to “push” the water through the check valve 140or can be mounted in the bellows to “pull” the water toward and throughthe check valve 140, depending upon the spring characteristics and thedesired delivery mechanism. The pressurization mechanism can be abellows assembly, a spring assembly, a piston assembly, and the like, asdiscussed further with regard to FIGS. 2 and 8 below. Spring assemblies,piston assemblies, and other pressurization assemblies can be locatedoutside the bellows to provide pressure to the bellows to pressurize thewater, or can be located within the bellows to provide direct pressureto the water as shown in the example in FIG. 1. For example, FIG. 2shows an example spring assembly 221 located outside the bellows 260.Outside spring assembly 221 exerts a force on the bellows 260 and thewater 199 in the bellows.

In addition, bellows assemblies can be self-pressurized as well. Forexample, a bellows assembly can be made of an elastic material known inthe art such as silicone, other rubbers and elastomers, including butnot limited to, latex, polychloroprene, polyester, nylon, polyurethane,and the like, that expand and contract as a volume of water is added tothe bellows assembly. In some self-pressurized examples, an aqueoussolution such as water is added to the bellows assembly, which expandsto hold the volume of water. The volume of water stretches the materialof the bellows assembly in a similar fashion to the manner in which aballoon or an inflatable bag expands when a volume of water is added tothe balloon. Once the desired volume of water is added to the bellowsassembly, the poppet (valve) can be closed to prevent the water fromleaving the bellows until the reaction is started. To start thereaction, the poppet on the bellows assembly can be opened to allow theaqueous solution to flow to the reactant material. The bellows assemblythen begins to return to its non-expanded size, which provides pressureto the water, and the water flows to the fuel cartridge 120. The poppet150 can be actuated by a physical connection of the fuel cell to thewater tray. The poppet may also be actuated by other mechanical orelectro-mechanical mechanisms may be used. Other valve designs can beutilized to perform the starting and stopping poppet function.

In another example, FIG. 8A shows an exploded view of a reservoirportion 832 of the water feed tray 130 that incorporates a springassembly 834 that is fitted in the water feed tray 130 to pressurize thewater 199. Spring assembly 834 can be an inverted spring where the innercoil is pulled through the outer coil during use. The inverted springeffectively increases the length of the spring assembly 834, and createsa more linear force range over the displacement range. This linear forcecan then be transferred to the water and/or to a bellows assemblyholding the water. As the inverted spring provides force to pressurizethe water, the inverted spring decreases in length, however even whenthe inverted spring reaches the state where it is flat, the spring isstill in a stressed state (providing force). This allows the water to beunder pressure even when almost all water (in the bellows or in thereservoir portion of the water tray) has been used. When unlocked, thespring assembly 834 imparts a force on the water by pulling on thebellows door assembly (for example, resulting in pressurized water ofapproximately 2-4 psi). The pressure is used to feed the water flow fromwater tray 130 to fuel cartridge 120 to begin the reaction. The springassembly 834 can be a traditional coiled spring 872 or can be made of astamped piece of metal that is elongated and heat treated such that whenthe spring assembly 834 is flat in the bellows assembly 260 it is stillin a stressed state (remains under pressure). In this fashion, thespring mechanism is configured such that there is positive spring forcethat results in pressurized water even when almost all the water hasbeen fed out of the bellows assembly 260.

Returning to FIG. 1, pressurized water 199 or liquid solution flows intothe fuel cartridge 120 from the water feed tray 130 through a checkvalve 140 and poppet 150. Hydrogen 188 is generated inside the fuelcartridge 120 and flows into the fuel cell 110. A diagram showing theflow of water 199 pressurized by a bellows assembly 260 through a poppet150 and check valve 140 into a fuel cartridge 120 is shown in furtherdetail in FIG. 2. The water 199 shown in FIG. 2 enters a water chamberand bellows assembly 260. For simplicity water 199, both in and out ofthe bellows assembly is shown as reference numeral 199. When the water199 reacts with the reactant fuel material 177 in the fuel cartridge120, hydrogen 188 is produced and flows from the fuel cartridge 120 tothe fuel cell (not shown separately in FIG. 2).

Spring-driven reaction systems can use the characteristics of the springto monitor and determine the amount of the reactant fuel material thatremains in the reactor chamber, such as fuel cartridge 120. Thedetermination can be made either directly or indirectly. With a knownamount of reactant fuel material in the fuel cartridge at the beginningof a reaction, the pressure in the fuel cartridge is monitored. As thepressure inside the fuel cartridge changes, the amount of water added tothe reaction can be determined, which provides an indication of theamount of reactant fuel material that was used in the reaction.Subtracting the amount of reactant fuel material used from the amount ofreactant fuel material at the start of the reaction provides the amountof reactant fuel material remaining for use in the reaction. Forexample, at the beginning of a reaction, a known amount of reactant fuelmaterial exists in the fuel cartridge 120. A spring, such as spring 221in FIG. 2 develops pressure in the water chamber (bellows assembly 260),and water 199 is injected into the fuel cartridge 120 via check valve140 and poppet 150. Hydrogen is generated as water 199 contacts thereactant fuel material 177 in the fuel cartridge 120. As spring 221provides the pressure to inject water 199 into the fuel cartridge 120,hydrogen is generated, which creates pressure in the fuel cartridge 120.The pressure created in the fuel cartridge 120 applies an opposite forceon the water chamber (bellows assembly 260), when the pressure in thefuel cartridge equals the water pressure created by the flow, the waterflow will stop which in turn means that additional hydrogen generationwill also stop. In the event that the hydrogen pressure in the fuelcartridge 120 inadvertently exceeds the water pressure created by thewater flow, the check valve will not allow the water to develop a higherpressure than the pressure determined by the spring. Without the checkvalve, the system could oscillate uncontrollably. As the reactioncontinues over time, the effective spring force can be seen as decayingover that same time period due to force versus deflectioncharacteristics of the spring. As the displacement of the spring changesover time, the water pressure changes, which is directly related to theaverage hydrogen pressure in the fuel cartridge over the same time. Ameasurement of spring displacement, water pressure, or hydrogen pressurecan be therefore used to indirectly determine the state of the reaction.For example, the system may be characterized so that at the beginning ofthe reaction, the developed pressure in the fuel cartridge is 3 psi butnear the end of the reaction, the pressure in the fuel cartridge is 1psi. A microcontroller with a look-up table (database) can be used tomeasure this pressure and to determine the state of the reaction. Thepressure sensor and the microcontroller may reside in the fuel cell, inthe water tray, in the pathway between the water tray and the fuelcartridge, in the fuel cartridge, or in any combination of them.

The spring force is based upon the physical characteristics of thespring, such as material, wire diameter, diameter of the shaft, internaland external diameters, pitch, block length, free length, number ofcoils, spring rate, and lengths at force. The spring can be of any of awide variety of different types such as coil, leaf, or clock springs.Based upon these physical characteristics, the effective force producedby the spring can be used to determine the hydrogen pressure in thereactor chamber, the amount of reactant fuel material that has beenreacted or similarly, how much reactant fuel material remains in thereactor chamber. Likewise, the effective spring force can be monitoredusing a force gauge, such as force gauge 288 to monitor, determine, andreport the effective force of the spring and thereby the pressureproduced by the hydrogen gas. Of course the force gauge 288 can also beinstalled in the reactor chamber to monitor the hydrogen pressureproduced from the reaction. Similarly, a pressure gauge can also beused. From these pressure and/or force measurements, the amount ofreactant fuel material remaining in the fuel cartridge 120 can bedetermined. For example, a simple look up table and/or database mappingcan be used to map effective spring force to the amount of reactant fuelmaterial remaining in the fuel cartridge 120. Likewise, a similar tablecan be employed mapping the hydrogen pressure in the fuel cartridge 120to an amount of reactant fuel that has been reacted. Combinations andvariations of these database mappings/look up tables can also beemployed.

Returning to FIG. 1, the fuel cell 110 utilizes the hydrogen 188 fromthe fuel cartridge 120 and oxygen from the air to create an electricpotential. Once the electric potential is created, the system 100 can beused to charge and/or run electronic devices, such as a cellulartelephone 2201 as shown in FIG. 22. Adapter cables 2202 can be fashionedto operably connect the system 100 to the electronic devices. Of course,other electronic devices may use the electric potential created by thesystem 100 to charge, or run, or operate. In this disclosure, the fuelcell 110 is considered to be a fuel cell system. For example, a fuelcell system can contain multiple fuel cells, a fuel cell stack, abattery, power electronics, control electronics, electrical outputconnectors (such as USB connectors), hydrogen input connectors, and airaccess locations to provide air for both cooling and for the reaction.

The fuel cell (system) 110 can be attached to the water feed tray 130and/or fuel cartridge 120 using a number of different techniques. Asshown in FIG. 6A, for example, the fuel cartridge 120 is inserted inwater feed tray 130, which is then secured to fuel cell 110 using guiderails 662 a, 662 b on the water feed tray 130 and guide rail 664 on thefuel cell 110. As the fuel cell 110 is slid along direction arrow F ontothe water feed tray 130, spring latch 666 is displaced until acalibrated notch (not shown separately) is engaged to securely preventbi-directional sliding of the system 100. FIG. 6B shows the securedposition of the system.

An alternative manner of mechanically securing the fuel cell 110 to thewater feed tray 130 and fuel cartridge 120 is shown in FIG. 6C. In thisexample, the fuel cell 110 is not mechanically slid and locked to thefuel cartridge 120 and/or water feed tray 130, but rather, the fuelcartridge 120 is captured by the water feed tray 130 and fuel cell 110using latches 668 a, 668 b. Latches 668 a, 668 b can be used to securelyclamp the water feed tray 130 to the fuel cell 110 during hydrogengeneration operations by using compressive force for engagement withlatch locking points 669 a, 669 b on the water feed tray 130 to preventthe fuel cell 110, water feed tray 130, and fuel cartridge 120 fromseparating.

Regardless of the manner in which the fuel cell 110 is ultimatelysecured to the water feed tray 130 and fuel cartridge 120, when properlyconnected, the fuel cell 110 pushes on the poppet 150 in the water feedtray 130 while simultaneously pushing the fuel cartridge 120 into thewater feed tray 130 and onto the water tray needle 682 as shown in theside view depicted in FIG. 6D (and schematically in FIGS. 1 and 2). Thevalve poppet 150 and needle 682 combination are configured such thatwhen the fuel cell 110 is engaged to the water feed tray 130, the poppet150 is depressed, and pressurized water 199 from the bellows 260 isallowed to travel through the water feed tray 130 along water pathway535, through the water tray needle 682, and into the fuel cartridge 120.To avoid spillage, the water feed tray 130, fuel cartridge 120, and fuelcell 110 are properly dimensioned with appropriate tolerances so thatwater 199 flows only when water feed tray needle 682 is inserted into agrommet 625 (see also needle valve 1329 in FIGS. 13A and 13B) within thefuel cell cartridge 120. Once water 199 reaches the reactant fuelmaterial 177 in the fuel cartridge 120, hydrogen gas will formgenerating a pressure inside the fuel cartridge 120. The generatedpressure will supply hydrogen 188 to the fuel cell 110 while alsoserving to limit the amount of additional water 199 that is input fromthe bellows 260 into the fuel cartridge 120.

As also shown in FIG. 6C, spring mechanism 670 can be employed to assistin ejecting the fuel cartridge 120 from the water feed tray 130. Forexample, the spring mechanism 670 can impart a physical force to fullymove/eject the fuel cartridge 120 from the water feed tray 130 or topartially move/eject the fuel cartridge 120 from the water feed tray 130to make it easier for a user to fully remove and/or to disconnectconnect the fuel cartridge 120 from a water inlet point, such as thewater inlet point 122 as shown in FIG. 2. Additionally, as shown in FIG.6D, the spring mechanism 670 raises the fuel cartridge off of the waterfeed tray needle 682, so even if the plunger 533 in FIG. 5A wasaccidentally pressed, hydrogen production would be prevented. Anadditional view of the water feed tray 130 illustrating spring mechanism670 is shown in FIG. 20.

Additional structural and operation details regarding the system 100,including water feed tray 130, fuel cartridge 120, and fuel cell 110 areprovided below. The additional disclosure materials below describeadditional structural and functional details of the water feed tray,fuel cartridge, and fuel cell in accordance with the claimed invention.

Water Feed Tray Feeding

FIG. 4A illustrates a water feed tray 130 with a fuel cartridge 120inserted. The fuel cartridge 120 shown includes an aluminum canister 421and a plastic canister cap 423 with a hydrogen port 424. Water feed tray130 can be divided into three major sections, including a bellows/waterfeed section 491, valve and poppet section 492, and fuel cartridgeholder section 493. The water feed tray 130 can include a guide rail 662for engaging or attaching the fuel cell 110. The water feed tray 130 canbe made of an insulating plastic, such as a thermoplastic,polycarbonate, PC/ABS blend, or other material that provides for safehandling of the fuel cartridge 120. As shown in a side view in FIG. 4B,the example insulating plastic pattern can include slits 494 or othervent holes in the plastic for heat transfer and to allow for heatgenerated from the fuel cartridge 120 to dissipate as water 199 is fedto the fuel cartridge 120. Further, spray-on or other heat insulatingmaterials, such as foams, aerogels, silicones, and the like can be addedto the canister to provide insulation for a user and to allow safehandling and/or to provide thermal insulation to raise internal reactiontemperature. Additionally, the insulating plastic can include feet 495to provide a stand for the water feed tray 130. The insulating plasticcan also include a tilted boss 496 for additional strength anddurability and can also be used as an alignment device to ensure propermating of the water feed tray and fuel cell 110.

The water feed tray 130 includes the water 199 that is pressurized anddelivered to the fuel cartridge 120. As outlined above and shown in FIG.2, the water feed tray 130 can utilize a bellows assembly 260 to containand hold the water 199. Alternative methods of holding, pressurizing,and delivering the water 199 can also be used as outlined above. Forexample, sliding pistons, collapsing diaphragms, inflatable diaphragms,and other deformable containers can be used as well as electrical pumps,such as piezoelectric pumps, and the like.

As shown in FIG. 3, the water feed tray 130 can have an access door 336to allow the user to easily fill or scoop water into the water feed tray130. In another example implementation, the water feed tray can besealed and a pump, syringe, or other pressurized water source can beused to fill the water feed tray 130 or to push water into a bellowsassembly. In one example implementation, the access door 336 can act asa lever arm allowing for easier loading of a spring (such as invertedspring 834 shown in FIG. 8A and stamped plates in FIGS. 8B and 8C) thatcan provide water pressure.

As shown in FIGS. 3 and 8F, the water feed tray 130 can have an accessdoor 336 to allow the user to easily fill or scoop water into the waterfeed tray 130. A user can press down on bellows access door 336 todisengage a locking shelf 815 and prepare the water feed tray 130 foruse. Access door 336 can provide access to the bellows (not shownseparately in FIG. 3) to contain and hold the water 199. For example,the door/bellows combination can be rotated or translated to put thespring 834 into a locked position, which loads the spring 834. In thelocked position shown in FIG. 8E, the user can easily add more water tothe bellows 260 without the bellows self-collapsing. Once the bellows260 is filled with water 199, the user locks the bellows door 336 closedas shown in FIG. 8F, which seals the water 199.

An example of the spring 834 in its nominal (down) position is shown inFIG. 8B. When fully assembled in the water feed tray 130, the spring 834is pulled through itself in the opposite direction (up) to load as shownin FIG. 8C.

As further shown in FIG. 8D, the bellows 260 assembly can then berotated or translated off a locking shelf 815 to activate the spring834. The spring 834 then pressurizes the water 199 in the bellows 260where it can flow to fuel cartridge 130. Of course other lockingmechanisms can be used to gain access to the bellows 260 to add water199 and to load the spring 834. For example, locking pins 1138 a, 1138b, 1139 can be used to secure the bellows 260 as shown in FIG. 11.Additionally, sliding rods 1242 can be used to gain access to thebellows 260 to add water 199 and to load the spring 834. Examples of thesliding rods 1242 are shown in a locked position in FIG. 12A and in anunlocked position in FIG. 12B.

As shown schematically in FIGS. 1 and 2, after the locking mechanism isdisengaged, the water 199 is ready to be delivered to the fuel cartridge120. FIG. 5A shows an exploded view of the water feed tray 130, a watertray insert 531, and a fuel cartridge 120 and water pathway 535 thatconnects a bellows assembly (not shown separately in FIG. 5) to the fuelcartridge 120.

In one example implementation, a plunger 533 in poppet 150 is in linebetween the bellows assembly containing the water and the fuel cartridge120. A detailed drawing of the plunger 533 and poppet 150 in an openposition (water 199 flowing from bellows to fuel cartridge 120) is shownin FIG. 19A, and a drawing of the plunger 533 and poppet 150 in a closedposition (water 199 not flowing from bellows to fuel cartridge 120) isshown in FIG. 19B. The plunger 533 keeps water 199 from leaving thebellows assembly during storage or while the user is preparing a fuelcartridge 120 or loading a fuel cartridge 120.

During storage, transportation, and in other instances where safetydictates that the water-reactant fuel reaction not initiate, the plunger533 in poppet 150 can be locked in its closed position so that no watercan flow to the fuel cartridge. This interaction works as a stop valveon the water feed tray. The action of closing the plunger 533 can beactuated by additional mechanical means such as levers, switches,actuators, and electrical switching means such as an electricallyactuated switch, magnetic switch closures mounted on the fuel cell, thewater tray, and/or the fuel cartridge. An example of a magnetic stopvalve closure mounted on the fuel cell is illustrated schematically inFIGS. 26A and 26B. In FIG. 26A, a magnet 2611 in the fuel cell (notshown separately) is coupled to the water feed tray/fuel cartridgecombination, which contains a magnetic poppet 2622. The magnet 2611 actsupon the poppet 2622 holding the poppet 2622 above the water path 2633allowing water to flow as shown by reference arrow W. In FIG. 26B, themagnet 2611 is moved away from magnetic poppet 2622 (such as when thefuel cell is detached from the water feed tray/fuel cartridgecombination). This allows the poppet to move into the water path 2633blocking the flow of water through water path 2633. In this closedposition, water can only flow back and forth as shown by referencearrows B and F. Other mechanical, electro-mechanical, ormagneto-mechanical devices can also be used to actuate the valve and toprevent water from traveling from the pressurized water chamber into thefuel cartridge until the water feed tray and/or the fuel cartridge isconnected to the fuel cell. In the case where the fuel cartridge and thewater feed tray are incorporated in an integrated unit, the switchingdevice can be used to prevent water flow until the integrated unit isconnected to the fuel cell. In another example implementation, the stopvalve could simply be locked in shipping, and a user would pull the stopvalve mechanism actuating the cartridge, and allowing the reaction tostart.

Returning to FIGS. 1, 2, 19A, and 19B, the plunger 533 is opened andwater 199 is allowed to travel along water pathway 535 when the fuelcell 110 is engaged and locked into position with the water feed tray130 as described above. The water tray insert 531 can be integral to thewater feed tray 130 or can be attached using a number of sealingmechanisms including glue/epoxy, ultrasonic bonding, physicalcompression, gaskets, and the like. An example of an ultrasonic weldingbead is shown as reference numeral 572.

When the fuel cell 110 is disengaged from the water feed tray 130, thewater flow will stop as a spring 537 puts the valve spring into itsnormally closed position (shown in FIG. 19B). The plunger 533 and/orpoppet 150 can also be an electronically actuated valve(s) where asensor(s) is used to detect connection/disconnection of the fuelcartridge 120, water feed tray 130, and fuel cell 110. In one exampleimplementation, a permanent magnet is constructed as part of the valveassembly. An electrical coil and appropriate drive electronics can belocated in the fuel cell 110, which can be integrated with existing fuelcell control electronics. Additionally, a miniature pump can also beused to deliver the water under pressure. A miniature pump also allowsfor control of the water flow rate which can generate a hydrogenpressure. A control scheme can be used to control the pressure to adesired value or within a nominal range.

In addition to the spring mechanism 670 shown in FIG. 6C and FIG. 20that can be employed to assist in ejecting the fuel cartridge 120 fromthe water feed tray 130, a spring mechanism 497 (shown in FIG. 4B) canalso be used to push the fuel cartridge 120 against the fuel cell 110 toprovide the force required for a gas (hydrogen) seal. The springmechanism 497 can be a physical spring, such as helical or coil springs,compression springs, flat springs, beams, and the like. For example, thespring mechanism 497 can impart a physical force to fully seal andstabilize the fuel cartridge 120 to the fuel cell 110 such that thehydrogen port 424 of the fuel cartridge 120 provides hydrogen to thefuel cell 110 without leakage.

As described above, when a spring 834 is used in conjunction with abellows assembly 260 to pressure the water 199, the system 100 providesan additional mechanism to prevent transient high pressure spikes fromreverse-pressurizing the spring 834. The high pressure spikes can resultin perturbations in pressure and water delivered at an oscillating rate.If the spring 834 is reverse-pressurized, higher water surges can resultin oscillatory and/or a positive feedback situation resulting inunintended escalating pressure spikes. Multiple methods can be utilizedto prevent transient high pressure spikes from reverse-pressurizing thespring 834. For example, in one implementation outlined above withregard to FIGS. 1, 4, and 8, a check valve 140 can be used to isolatepressure spikes to the fuel cartridge holder section 493 side of thewater feed tray 130. The check valve 140 in tandem with the spring 834provides pressure regulation to isolate pressure spikes and to eliminateoscillating amounts of water delivered to the reactant fuel material177. The check valve 140 can be integral to the water 199 storage andfeed, located separately in a check valve and poppet housing 745 orincluded as part of fuel cartridge 120. When the check valve 140 isplaced prior to the reactant fuel mixture 177, perturbations in pressurecan be eliminated and uniform volumes of water 199 can be delivered tothe reactant fuel mixture 177 in the fuel cartridge 120. Othermechanisms to prevent transient high pressure spikes fromreverse-pressurizing the spring can also be employed, such as acontrolled on/off valve can be used to eliminate perturbations inpressure and water delivered at an oscillating rate. Another device thatcan be used is a bleed-off valve, which can simply vent any excesspressure either by way of a valve or through the fuel cell 110. In eachcase, a check valve in combination with the spring can be used toeliminate fluctuations in water pressure and flow rates to the fuelcartridge 120.

As shown in FIG. 18B, a water flow limiter, such as water flow limitingorifice 1886 can be used to prevent excessive water flow from beingdelivered to the fuel cartridge 120 in certain transient conditions. Thewater flow limiting orifice 1886 can serve as a safety limiter of thewater input rate. The water flow limiting orifice 1886 can regulate therate of the delivered water to provide sufficient time for the chemicalreaction between the reactant fuel material 177 and the water 199 togenerate hydrogen pressure. Failure to limit the water flow can causeexcessively large amounts of water to be delivered to the fuel cartridge120 resulting in high pressure spikes. A flow limiting orifice can beincorporated in the fuel cartridge, water feed system, or both. Forexample, in one implementation shown in FIG. 18B, the water orifice 1886could be 0.007 inch hole in a solid disc that is pushed into the tubingor the grommet. A detailed view of a tube connection water flow limitingorifice is shown in FIGS. 9A-9C, while a disk type water flow limitingorifice is shown in FIGS. 10A-10C. In another implementation, it can bemolded directly into one of the rubber water distribution components. Inthe implementation shown, the orifice is fabricated as part of barbedfitting which allows it be coupled directly to tubing. In anotherimplementation, one side of the barbed water orifice can be inserteddirectly into the grommet without need for an additional interfacefitting.

Fuel Cartridge

As shown in further detail in FIGS. 13A, 13B, and 14A, the fuelcartridge 120 is designed for the “water-reactive” class of cartridges.That is, the reactant fuel material 177 in the fuel cartridge 120undergoes a chemical reaction with water. The chemical reactiongenerates hydrogen gas, which is combined with oxygen or anotheroxidizing agent in the fuel cell 110 to generate electricity.

In one example implementation, the fuel cartridge 120 is constructedusing a thin-walled metal canister 1426 that includes a water-reactivefuel material 177 (powder) and a plastic top cap 1327. The metalcanister 1426 can be sized for convenient handling and use inconjunction with the water feed tray 130. For example, the metalcanister 1426 can be circular with a range of diameters, some being frombetween 40 and 60 mm, such as the 51 mm diameter shown in FIGS. 13A,13B, and 14A. The canister 1426 can be made with a range of heights,some being from between 10 and 30 mm, such as the 19 mm height shown inFIGS. 13A, 13B, and 14A. The canister 1426 can be made of impactextruded aluminum and can be plated with other materials, such asmetals, polymers, or epoxys, for example. A plastic top cap 1327 can beused to seal the canister 1426. Canisters and caps of other materials,such as all plastic, all metal, rigid-walled, flexible-walled, can alsobe used and can be selected based upon the type of water-reactive fuelmaterial used, whether water or a different solution is used, whetherthe fuel canister and/or cap is to be re-used.

As shown in FIGS. 15C and 15D, an overmolded face seal gasket 1537serves to seal two surfaces which are parallel to each other. Often,when injecting into a rubber material, the injecting device can leave arough surface or extra material at the point of injection 1555. An extramaterial (called “flash”) can be left at the site where the two toolscome together. The overmolded face seal gasket 1537 of the claimedinvention is configured to allow the injection point of the over-mold tobe on a surface other than the sealing surface. That is, the point ofinjection 1555 of the rubber is offset from the seal points 1566, 1567where the cap 1527 and the path of the hydrogen output 1588. Duringmanufacture, the injection rubber first fills the horizontal valley ofovermolded face seal 1537 and then flows up to form a flash free pointat the hydrogen seal 1566. The result is a smooth hydrogen seal surface.The sealing surfaces include, but are not limited to, sodium silicidecartridge I/O ports and fuel cell I/O ports, including hydrogen outputport 1588. The face seal gasket 1537 prevents radial leakage of hydrogengas or other fluids. The overmolded design provides for a single capcomponent (as shown in FIG. 15D), which decreases cost.

Returning to FIGS. 13A, 13B, and 14A, in one example implementation, thecanister 1426 can be connected to the cap 1327 by a mechanical crimp.Plastic top cap 1327 can be crimped to seal the fuel cartridge 120 usingcrimping tool 1606 as shown in FIG. 16. Crimping tool 1606 can be usedto make a rollover crimp in construction of the fuel cartridge 120 asshown in FIG. 16B. In this example, the fuel cartridge 120 body includesthe metal canister 1426 and the cap 1327. By applying pressure throughthe press crimping tool 1606 directly down onto the canister and cap,the wall of the canister 1426 rolls over the top of the cap 1327. Thisenables the use of very thin walled fuel cartridges while providing ahighly robust cap restraint mechanism. This technique and constructioncan also readily be fabricated in high volume production using a rapidvertical compression to create the rollover cartridge crimp.

As shown in FIGS. 13A and 13B, alternatively (or in combination), thefuel cartridge 120 can also include a sealing screw 1313 and threadedPEM standoff 1314 combination to secure the cap 1327 to the canister1426. The screw/standoff combination can be connected inside or outsideof the can. The screw/standoff approach allows for reusable caps 1327and canisters 1426, while crimp connections allow for lower weight,lower cost, and disposability. Of course other types of joiningmechanisms and fasteners such as glue, epoxy, welds, bolts, clips,brackets, anchors, and the like can also be used. Fuel cartridge 120 canalso include a filtration assembly 1359 that can be used to filter thehydrogen 188 before it is used in the fuel cell 110.

Shown in FIGS. 13A and 13B, the valve between the fuel cartridge 120 andthe fuel cell 110 is referred to as the cartridge valve 1328. Anotherexample of a cartridge valve integrally mounted to the cap 1327 is shownin FIGS. 17A-17D. In the implementation shown, the orifice in theplastic cap 1327 provides the core function of a cartridge valve (i.e.hydrogen flow control) in a simple-to-manufacture package. Cartridgevalve 1328 can include an o-ring type compression fitting about theorifice, for example, using a compression force of up to approximately20 N to compress the o-ring at a distance of 1.5 mm.

In some example implementations, the fuel cartridge 120 can have twosealed locations, where one sealing location (cartridge valve 1328)allows hydrogen 188 to pass from the fuel cartridge 120 to the fuel cell110, and another sealed location (needle valve 1329) allows water 199 tobe inserted into the fuel cartridge 120. In FIG. 21A, a perspective viewof the needle valve 1329 is shown. Also, in FIG. 21B, a detailed crosssectional view of the needle valve 1329 is shown. The needle valve 1329can be constructed along the functional lines of a sports ball grommet.As a water sealing device, needle valve 1329 allows water, liquids, orother solutions to be inserted into the canister 1426 via a needle orother penetrating source. Upon removal of the needle or penetratingsource, the liquid will not drain or otherwise flow from the fuelcartridge 120. In one or more example implementations, a siliconegrommet is used as the needle valve 1329 and is opened with theinsertion of the water feed tray needle 682. Upon removal of the fuelcartridge 120 from the water feed tray 130, the water feed tray needle682 is removed from the fuel cartridge 120, and the silicon grommetself-closes to form the seal.

The needle valve 1329 can be constructed of silicon, or other rubbers,with a number of different hardness specifications and dimensions. Forexample, the needle valve 1329 shown in FIGS. 13A, 13B, 21A and 21B is asilicon grommet with a 1/16″ inside diameter needle entry point 2158.This would permit a 22 gauge needle to enter the valve 1329. The heightand width of the needle valve can also vary based upon the size of thecanister 1426, fuel tray 130, water feed tray needle 682 and othercomponents. For example, the needle valve 1329 shown in FIGS. 13A, 13B,21A and 21B is a silicon grommet with a 5/16″ height, extending 3/16″outside of the canister 1426. Similarly, the water distribution point2157 can vary in size and specification as well. Water distributionpoint 2157 is where a reaction feed tube (not shown in FIGS. 21A and21B) attaches to deliver water to the reactant fuel material to beginthe reaction. Water distribution point 2157 can also vary in size andgeometry such that water can travel straight through the needle valve(as shown in FIG. 21A and FIG. 21B) or can pass through at an angle (asshown in FIG. 13A and in FIG. 13D). For example, in FIG. 13D, the needlevalve 1329 uses a grommet where the water 199 from the water feed tray130 travels vertically into the canister while the water comes out ofthe grommet at a 90 degree angle into the canister 1426. The angledneedle valve shown in FIG. 13D facilitates a low-profile canisterdesign.

As shown further in FIG. 23A, for additional fluid isolation, a siliconesheet 2353 can be added on top of the needle valve 1329. Silicone sheet2353 collects any liquid droplets off the edge of the water feed trayneedle (not shown separately in FIG. 23). This additional measure offluid isolation can serve to protect against liquids having a high pH,which could shed droplets. The water feed tray needle can, at times,have a droplet or a residual spray come out of it. The silicone sheet2353 structure creates a void 2354 volume for the capture of any liquidupon removal of the water feed tray needle. An illustration of the waterfeed tray needle 682 being pulled out and stretching a silicone sheet2353 and creating a void space is shown in FIG. 23B. A bottom view ofthe silicone sheet 2353 is shown in FIG. 23C. Additionally, a needlevalve can be fabricated to perform both functions of the needle valve1329 and silicone sheet 2353 in a single component.

As shown in FIG. 18A, the reaction feed tube 1883 is inserted inside thefuel cartridge and connected to the water distribution point 2157 todistribute of water 199 throughout the fuel cartridge 120. In oneexample implementation, silicone is used as the reaction feed tube 1882,and small holes 1884 a, 1884 b, 1884 c are used for water dispersion.Small holes 1884 a, 1884 b, 1884 c in rigid tubing may have a tendencyto clog due to the byproducts of the reaction in the fuel cartridge 120.The holes 1884 a, 1884 b, 1884 c can be precision-drilled, molded, orprecision punched. In one example implementation, the holes in thesilicone reaction feed tube 1883 will self-enlarge around blockages dueto the flexibility of the tubing.

In one example implementation shown in FIG. 18B, a T-fitting 1884 can beused to connect the reaction feed tube 1883 to the water distributionpoint 2157. The T-fitting 1884 allows for rapid hand-assembly of thereaction feed tube 1883 and allows customization of the reaction feedtube and the delivery of the water to the reactant fuel material. As wasthe case with the reaction feed tube 1883 of FIG. 18A, similar silicone(or other flexible) tubing employing a T-fitting 1884 can utilize a holeor a series of holes to control the uniformity, speed, and amount ofwater distributed by the reaction feed tube to the reactant fuelmaterial. For example, holes can be fabricated in a wide range ofdifferent sizes and locations. The T-fitting 1884 allows for the use ofsilicone or other flexible tubing without custom molding. The T-fitting1884 also allows for the tubing to stay in a controlled area. Without aT-fitting, the tubing of the reaction feed tube 1883 has a tendency tospring out towards to the walls of the canister 1426. If water isdelivered to the reactant fuel material using this configuration, thewater could pool in areas near the canister walls and not reach all ofthe reactant fuel material. The T-fitting allows for the tubing to bekept off the wall without the need of glue, other mechanical supports,or custom molded components and provides a uniform distribution of waterto the reactant fuel material. However, these other supports can be usedtoo.

The fuel cartridge 120 can be segmented such that each time the fuelcell 110 is attached to the water feed tray 130 (or attached to theintegrated combination of a water feed tray and a fuel cartridge inthose water reactive hydrogen fuel cell power systems where the fuelcartridge is not a separate physical device from water feed tray) wateris provided to a different portion of the fuel cartridge, therebyreacting with unspent reactant fuel material. For example, as shown inFIG. 24A and discussed below with regard to the fuel cartridges, oneexample fuel cartridge 2420 can be divided into a number of sections2421, 2422, 2423, 2424, 2425, 2426 within which reactant fuel materialcan be provided. For clarity and brevity, in FIG. 24A six sections 2421,2422, 2423, 2424, 2425, 2426 are illustrated, but fuel cartridge 2420can include any number and configurations of sections, such as tensections for example. The sections can be radially oriented as shown inFIG. 24A with dividing walls 2460 separating each section, or can beoriented in other configurations with which to separate portions of thereactant fuel material. In the example configuration shown in FIG. 24A,fuel cartridge 2420 also includes a rotatable actuator manifold 2450that is used to select the section of the fuel cartridge to which wateris to be delivered. Each time fuel cell 110 is attached to the waterfeed tray and fuel cartridge combination, rotatable actuator manifold2450 engages with a needle (such as water feed tray needle 682 as shownin FIG. 6D, for example). Upon attachment, the water feed tray needle(not shown in FIG. 24A) causes the rotatable actuator wheel 2350 torotate in step such that actuator wheel aperture 2470 rotates to the“next” section of the fuel cartridge. For example, FIG. 24A showsaperture 2470 providing access to section 2424 of the fuel cartridge2420.

In use, water 199 flows from feed tray 130 through water pathway 535 asshown further in FIG. 6D. Water 199 enters the fuel cartridge 120 viawater feed tray needle 682. As further illustrated in FIG. 24A, water isdistributed through aperture 2470 to the reactant fuel material presentin that section 2424 of the fuel cartridge 2420. After the reactiontakes place and the fuel cell 110 is used to provide power to a device,the fuel cell 110 can be removed from the water tray/fuel cartridgecombination.

With the sectional fuel cartridge 2420, the water-reactive,hydrogen-fueled power system 100 can be reused multiple times (forexample, the number of times can correspond to the number of sections inthe fuel cartridge 2420). When subsequently re-using the system 100, thefuel cell 110 is reconnected to the water tray/fuel cartridgecombination. Upon re-attachment, water feed tray needle 682 (shown inFIG. 6D) engages the rotatable actuator manifold 2450 which rotates andcauses the aperture 2470 to move from section 2424 to section 2425 asfurther shown in FIG. 24B. By rotating the aperture 2470 to section2425, water can now be delivered to the reactant fuel material presentin that section 2425 of the fuel cartridge 2420. Of course, this processcan be repeated multiple times as the fuel cell 110 is reused to chargeand/or provide power to a device.

Likewise, alternative techniques for delivering water to differentsections of the fuel cartridge can also be used. For example, waterdelivery can be affected by selecting different water tubes to deliverwater from a needle to the individual sections. As shown further in FIG.25A, the rotatable actuator manifold 2450 can include multiple ports2571, 2572, 2573 that can be selected, and water 199 from the water feedtray can be directed to different water tubes (not shown separately) andultimately to different sections of the fuel cartridge. A rotationinducing clip 2585 can be employed to rotate the manifold 2450 to selectthe appropriate tubes. As shown further in FIG. 25B, the one-wayrotation of the clip 2585 imparts a one-way rotation of the manifold2450 using directional teeth or fins, such as teeth 2586 on the rotationinducing clip 2585 of FIG. 25B. As outlined above, rotation of themanifold can be induced mechanically, electrically, magnetically, or thelike, depending upon the environment in which the system is used and theparticular application.

As shown in FIGS. 14G AND 14H, in one example implementation a reactantretention screen 1447 can be implemented to prevent both reactant fuelmaterial 177 from moving and/or clumping and to prevent the nucleationof high viscosity silicate bubbles. If the system 100 is operated whilethe fuel cartridge 120 is lying on its side or is upside down, the waterfeed tray 130 may not be adding water flow to the reactant fuel material177. The retention screen 1447 keeps the powder in close proximitywithin the canister 1426. In one example, a molded retention screen 1447can be fabricated with a diameter slightly larger than the innerdiameter of the wall of the canister 1426. The retention screen 1447 canbe pushed on top of the reactant fuel material 177 thereby consolidatingthe powder near the water distribution point of the fuel cartridge orunder the water tubing 1883 (shown in FIGS. 18A and 18B) resulting in auniform distribution of the reactant fuel material in proximity to thelocation of the water distribution. This configuration will provide amore uniform reaction than if the reactant fuel material weredistributed in a non-uniform fashion throughout the canister 1426.

Additionally, as outlined above, in one example implementation, a waterrestriction orifice 1886 can be provided between the water distributionpoint 2157 and the reaction feed tube 1883. In another example, thewater restriction orifice can be formed directly in the needle valve1329 or directly in the reaction feed tube 1883. The water restrictionorifice 1886 can be sized to limit the water flow to avoid excess waterat start of the reaction or in case of a fuel cartridge breach. In thefuel cartridge breach, no hydrogen back pressure develops to counteractthe spring pressure, which results in very high amounts of waterdelivered to the fuel cartridge, which in turns creates very high levelsof hydrogen flow.

In a hydrogen “valve-less” configuration shown here, no traditionalvalve is used between the fuel cartridge and fuel cell. Hydrogen isgenerated when the fuel cell 110, fuel cartridge 120, and water feedtray 130 are connected, thereby eliminating the need for such a valve.Rather, as described above, a simple o-ring, face-seal, or other simpleseal mechanism between the fuel cartridge and the fuel cell are utilizedwithout the need for a normally closed valve for the storage of gaseoushydrogen. The water-reactive fuel cell cartridge regulatory safetyrequirements require passing a water immersion test without significant(if any) hydrogen generation. A separator membrane can be used to keepwater from back-diffusing through the hydrogen output orifice into thefuel cartridge materials that are water reactive. The cartridge valve isclosed to prevent entry of water into the cartridge when it is notconnected to the water feed tray and fuel cell.

For example, in one implementation, the hydrogen separator membrane canbe heat-staked to the fuel cartridge cap. In one example implementation,the hydrogen separator membrane contains a scrubber to ensure hydrogenpurity. As shown in FIGS. 15A and 15B, the cap can include hydrogenpathways (FIG. 15A) or a maze (FIG. 15B) inside the cap to provideadditional separation and filtration capabilities. For example, CuO canbe used. Additional scrubber materials can also be employed in thepathways depending upon the type and amount of potential contaminantsthat may be present. The scrubbers and separating membranes can bechosen to ensure that high purity hydrogen gas is delivered to the fuelcell. In one example implementation, a sheet is used between thescrubber and the membrane separator to provide a long path-length over afilter bed.

Fuel cells typically operate on a given pressure where the hydrogen flowrate is determined by the electrical current output. As outlined aboveand in FIGS. 13A and 13B, the cartridge valve 1328 between the fuelcartridge 120 and the fuel cell 110 is a hydrogen orifice that can serveas a hydrogen flow restriction orifice. That is, a flow-restrictionorifice in the top cap can be used to set or regulate the hydrogen flow(pressure) to the fuel cell. The developed hydrogen flow is determinedby the hydrogen orifice size and the developed hydrogen pressure, whichis determined by the delivered water pressure (to the reactant fuelmaterial). In the claimed invention, the fuel cell dynamically adjuststo the developed hydrogen flow. The fuel cell increases fuel consumptionif hydrogen is available and decreases consumption if not available bycharging or discharging a battery (in the fuel cell) at a constant load.The cartridge valve (hydrogen orifice) and the pressure developed by thewater feed system spring are used to set the hydrogen flow to an optimalflow range which enables the fuel cell to operate at a predictablecurrent. In this fashion, the hydrogen fuel cell of the claimedinvention is analogous to an electrical current-source, as opposed toprevious systems where hydrogen fuel cells were typically analogous toelectrical voltage sources. Alternatively, the hydrogen orifice can beused to simply set a maximum flow and the cartridge will self-regulateflow below the maximum level as determined by the developed pressure andorifice size. If a fuel cell consumes less than the maximum level andcontains a valve to build up internal fuel cell pressure (as is commonwith fuel cell systems), the fuel cartridge will self regulate andmaintain a nominal constant pressure and only generate the amount ofhydrogen required by the fuel cell.

As outlined above, the fuel cartridge can utilize sodium silicide powderas the reactant fuel material. For example, a 30 g fuel cartridge caninclude 4 g of sodium silicide powder. Approximately 10 ml of water ismixed with this energy-carrying reactant fuel material to produceapproximately 4 liters of hydrogen gas, resulting in an energy outputfrom the fuel cell of approximately 4 watt hours. The fuel cartridge iswater-proof, has a minimum shelf life of two years, can be stored attemperatures of up to 70° C., and can be used in operating temperaturesbetween approximately 0° C. to 40° C. to generate hydrogen gas to beused in fuel cell 110.

Fuel Cell

As outlined above, the claimed system incorporates a water-reactive fuelcell that utilizes a reactant fuel material, such as sodium silicide,for example, and water to generate hydrogen. One example fuel cell inaccordance with the claimed invention includes a 4 Polymer ElectrolyteMembrane (PEM) 1000 mAh cell fuel cell stack rated for a 5V, 500 mAinput and a 5V, 1000 mA output. One example fuel cell in accordance withthe claimed invention includes a Li-ion 1600 mAh internal buffer andutilizes a micro USB charging input port and a USB-A charging outputport.

An example fuel cell in accordance with the claimed invention has arated input (micro USB charging of the internal battery) of 2.5 W and arated total output of 2.5 W (fuel cell mode) and 5.0 W (internalbuffer/battery mode). One example fuel cell in accordance with theclaimed invention includes an internal buffer (battery) capacity of 5.9Wh (1600 mAh, 3.7 V). One example fuel cell in accordance with theclaimed invention is compact and portable with approximate dimensions of66 mm (width)×128 mm (length)×42 mm (height) and weighs approximately175 g (without water feed tray) and approximately 240 g (with the waterfeed tray).

Having thus described the basic concept of the invention, it will berather apparent to those skilled in the art that the foregoing detaileddisclosure is intended to be presented by way of example only, and isnot limiting. In addition to the embodiments and implementationsdescribed above, the invention also relates to the individual componentsand methods, as well as various combinations and subcombinations withinthem. Various alterations, improvements, and modifications will occurand are intended to those skilled in the art, though not expresslystated herein. These alterations, improvements, and modifications areintended to be suggested hereby, and are within the spirit and scope ofthe invention. Additionally, the recited order of processing elements orsequences, or the use of numbers, letters, or other designationstherefore, is not intended to limit the claimed processes to any orderexcept as can be specified in the claims. Accordingly, the invention islimited only by the following claims and equivalents thereto.

The claimed invention is:
 1. A hydrogen fuel cell system comprising: afuel cell; a fuel cartridge including an overmolded face seal gasketthat provides an offset injection point on the fuel cartridge; areactant fuel material in the fuel cartridge; and a water feed trayoperably connected to the fuel cartridge that provides an aqueoussolution into the fuel cartridge to react with the reactant fuelmaterial to develop hydrogen for the fuel cell.
 2. The hydrogen fuelcell system of claim 1, wherein the overmolded face seal gasket includesat least one of a fuel cartridge input port, a fuel cartridge outputport and a hydrogen output port.
 3. The hydrogen fuel cell system ofclaim 1, wherein the reactant fuel material includes a stabilized alkalimetal.
 4. The hydrogen fuel cell system of claim 1, wherein the reactantfuel material includes at least one of sodium silicide or sodium silicagel.
 5. The hydrogen fuel cell system of claim 1, wherein the water feedtray includes a bellows assembly that holds the aqueous solution.
 6. Thehydrogen fuel cell system of claim 5, wherein the bellows assemblyself-pressurizes the aqueous solution to be provided to the fuelcartridge.
 7. The hydrogen fuel cell system of claim 5 furthercomprising: a spring inside the bellows assembly that pressurizes theaqueous solution to be provided to the fuel cartridge.
 8. The hydrogenfuel cell system of claim 7, wherein the spring inside the bellowsassembly pushes the aqueous solution to the fuel cartridge.
 9. Thehydrogen fuel cell system of claim 7, wherein the spring inside thebellows assembly pulls the aqueous solution to the fuel cartridge. 10.The hydrogen fuel cell system of claim 5 further comprising: a springoutside the bellows assembly that pressurizes the aqueous solution to beprovided to the fuel cartridge.
 11. The hydrogen fuel cell system ofclaim 5 further comprising: a check valve that regulates aqueoussolution flow from the bellows assembly to the fuel cartridge based uponpressure of the aqueous solution from the bellow assembly and pressureof the hydrogen developed in the fuel cartridge.
 12. The hydrogen fuelcell system of claim 11, wherein the check valve regulates the pressureof the provided aqueous solution as a steady decay associated with thebellows assembly pressure.
 13. The hydrogen fuel cell system of claim11, wherein the check valve prevents hydrogen gas from deflecting thebellows assembly.
 14. The hydrogen fuel cell system of claim 11, whereinthe check valve dampens the pressure of the aqueous solution initiallyprovided to the fuel cartridge to start or restart a reaction.
 15. Thehydrogen fuel cell system of claim 1 further comprising: a poppet thatprevents the aqueous solution from traveling to the fuel cartridge whenthe poppet is in a locked position and enables flow of the aqueoussolution, actuates the fuel cartridge, and allows the reaction to startwhen placed in an unlocked position.
 16. The hydrogen fuel cell systemof claim 1, wherein the fuel cartridge is segmented into sections. 17.The hydrogen fuel cell system of claim 16 further comprising: arotatable actuator that selects a segmented section of the fuelcartridge to which the aqueous solution is to be provided.
 18. A methodof controlling a hydrogen fuel cell system comprising: inserting a fuelcartridge with a reactant fuel material into a water feed tray, the fuelcartridge including an overmolded face seal gasket with an offsetinjection point; connecting a fuel cell to the fuel cartridge; providingan aqueous solution from a bellows assembly to the fuel cartridge toreact with the reactant fuel material; and developing hydrogen from thereaction of the aqueous solution and the reactant fuel material.
 19. Themethod of controlling the hydrogen fuel cell system of claim 18 furthercomprising: delivering the developed hydrogen to the fuel cell.
 20. Themethod of controlling the hydrogen fuel cell system of claim 18, whereinthe reactant fuel material includes at least one of sodium silicidepowder or sodium silica gel.
 21. The method of controlling the hydrogenfuel cell system of claim 18 further comprising: self-pressurizing theaqueous solution to be provided to the fuel cartridge with the bellowsassembly.
 22. The method of controlling the hydrogen fuel cell system ofclaim 18 further comprising: pressurizing the aqueous solution to beprovided to the fuel cartridge with a spring inside the bellowsassembly.
 23. The method of controlling the hydrogen fuel cell system ofclaim 22, wherein pressurizing the aqueous solution includes pushing theaqueous solution to the fuel cartridge.
 24. The method of controllingthe hydrogen fuel cell system of claim 22, wherein pressurizing theaqueous solution includes pulling the aqueous solution to the fuelcartridge.
 25. The method of controlling the hydrogen fuel cell systemof claim 18 further comprising: pressurizing the aqueous solution to beprovided to the fuel cartridge with a spring outside the bellowsassembly.
 26. The method of controlling the hydrogen fuel cell system ofclaim 18 further comprising: regulating the flow of the aqueous solutionfrom the bellows assembly to the fuel cartridge with a check valve. 27.The method of controlling the hydrogen fuel cell system of claim 26,wherein regulating the flow of the aqueous solution with the check valveis based upon pressure of the aqueous solution from the bellows assemblyand pressure of the hydrogen developed in the fuel cartridge.
 28. Themethod of controlling the hydrogen fuel cell system of claim 27, whereinregulating the flow of the aqueous solution includes regulating thepressure of the aqueous solution as a steady decay associated with thebellows assembly pressure.
 29. The method of controlling the hydrogenfuel cell system of claim 27 further comprising: preventing hydrogen gasfrom deflecting the bellows assembly.
 30. The method of controlling thehydrogen fuel cell system of claim 14 further comprising: dampening thepressure of the provided aqueous solution initially delivered to thereactant fuel material to start or restart a reaction with a water flowlimiter.
 31. The method of controlling the hydrogen fuel cell system ofclaim 18 further comprising: preventing the aqueous solution fromtraveling to the fuel cartridge when a poppet is in a locked position,and enabling flow of the aqueous solution, actuating the fuel cartridge,and allowing the reaction to start when the poppet is placed in anunlocked position.
 32. The method of controlling the hydrogen fuel cellsystem of claim 18 further comprising: selecting a segmented section ofthe fuel cartridge to which the aqueous solution is to be provided.